Analytical Methods

Despite the large relative mass difference between different Ca isotopes, the isotopic variability of Ca in natural materials is relatively small. Consequently, high-precision Ca isotope analyses are required to accurately resolve Ca isotope fractionation prior to data interpretation. This chapter summarises techniques which are successfully used to digest samples and to purify different types of sample material. The basic principles of different mass spectrometric methods for the accurate and precise determination of Ca isotope compositions are presented with a focus on thermal ionisation mass spectrometry (TIMS) and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). We also present an overview about other, less frequently applied techniques used so far. Additionally, we provide useful information on how to report Ca isotope data (e.g. different notations and reference materials) and explain how to convert literature data based on different reference materials and/or given in different notations.